In an unconscious victim, the tongue can block the airway. To open it, you put one hand on the forehead, lift the chin with the other and tilt the head back. Then for 10 seconds you watch the chest move and try to feel the exhaled air on your cheek.
To check the breathing of an unconscious victim, you must first open the airway. Put one hand on their forehead and lift the chin with two fingers of the other hand, tilting the head back. Then, for 10 seconds, use the "look, listen and feel" method: watch the chest move, listen for breathing sounds and try to feel the exhaled air on your cheek.
Option 1. It mentions only watching the chest and leaves out the steps of feeling the airflow and opening the airway properly with a hand on the forehead.
Option 3. It says the head is not tilted back, which is dangerous, because in an unconscious person the tongue can block the airway.